Best solution for watching 4K content on internal home network
I know this has been asked numerous times, but I never seem to see the answers that help me out. I currently have a QNAP NAS TS-451+ with 8 TBs of usable storage. I have 7 TBs of content and some of that consists of 4K videos. I have recently upgraded by theater room to a Sony 4K 75 inch TV. I run all my media from a Plex server on my NAS either using the Plex app on my TV and in some cases I use DLNA. My issue is that I seem to have trouble streaming 4k content on my internal network from QNAP specifically unable to open the files at all and start watching them or continues to buffer, unless I shrink the video file, no matter what app I use to watch the video from. I prefer to take advantage of my TV and media system that I have now and view my content in 4k but at the same time I would prefer to limit my costs. I have considered buying another NAS that is marketed for 4K streaming, but I think there should be a cheaper way. I have tried Kodi and DLNA and I have similar issues with the 4K content when running from my NAS. Can I get some input on what improvements I should make to be able to watch 4k content internally only without ongoing buffering issues or unable to open them at all?
Not relevant but I have AT&T GB Fiber connection and I am running the Eero wireless devices for my internal network equipment. I have my home completely wired with CAT6.
My NAS as I mentioned is a QNAP NAS TS-451+ with 8 TBs of storage with a little under 1 TB free. I have about a TB of 4k content while everything else is 1080p and/or 720p
TV is Sony XBR75X940D with a hardwired network connection to it
I also have other media devices such as NVIDIA SHIELD (2015) and XBox One (not the S)
Plex runs on NAS connected via CAT6 connection to a gigabit switch
I am open to any suggestions or cheap alternatives. Thank you in advance!